In the majority of screen printing operations, more than one color is used to create the desired image. The use of more than one color results in using several screens, one for each color, wherein each screen has the associated image for that color. It is therefore necessary to ensure that the images from each screen align properly so that the associated colors align properly. This is typically done by ensuring that the screen is properly aligned in a frame and aligning the frame, such as a roller frame, to a platform, such as a pallet, which receives the article that is to receive the image.
One conventional method is to remove the pallet from the screen printing machine and install a fixture that has a series of pins. These pins are used to align the screen printing roller frame and screen in the machine. The screen printing roller frame is mounted on a flat bar having a hole and a slot in which to receive the pins, therein aligning the frame on the pallet. With the screen aligned, a frame holder having a U-shaped channel is secured to the screen printing roller frame, typically by lowering a bracket into engagement with the frame. With the frame secured in the frame holder, the frame and the pallet are moved relative to each other to separate them by either lowering the pallet or raising the frame with the frame holder. Depending on the type of machine either the pallet or the frame holders are rotated and another screen is inserted on the fixture and aligned with a second frame holder. After alignment of all the screens with the frame holder, the printer removes the fixture from the machine and reinstalls the pallet used for printing.
One of the shortcomings, in addition to the time required to remove the pallet and install the fixture, is that the installation and removal of the pallet and the fixture results in wear to those parts used to secure the fixture or pallet to a pallet arm. In addition, the printer must have a location to store the fixture when not being used to align the screen printing roller frame.
It is desired to have a registration system that would allow for quick registration of a screen printing roller frame and screen and in addition allow the registration means to retract without removal from the machine.